feat: wire computeKpis into the page render (#5)

src/routes/pages.js

@@ -1,10 +1,13 @@
 const express = require('express');
 const router = express.Router();
 const { getTopbarLocals } = require('../services/topbar-service');
+const { getAllRatingsFromDB, computeKpis } = require('../services/player-service');
 
 router.get('/', async (req, res) => {
   const topbar = await getTopbarLocals();
-  res.render('index', { activePage: 'players', ...topbar });
+  const players = await getAllRatingsFromDB();
+  const kpis = computeKpis(players);
+  res.render('index', { activePage: 'players', kpis, ...topbar });
 });
 
 router.get('/courses', async (req, res) => {

src/services/player-service.js

@@ -292,10 +292,30 @@ async function refreshAllPlayersInDB(progressCallback = null) {
   }
 }
 
+/**
+ * Aggregates KPI summary stats from an already-fetched player array.
+ * All fields are derived from the player list — no extra DB queries.
+ */
+function computeKpis(players) {
+  const active = players.filter(p => p.rating != null && p.rating > 0);
+  const avg = active.length > 0
+    ? Math.round(active.reduce((sum, p) => sum + p.rating, 0) / active.length)
+    : null;
+
+  return {
+    tracked: players.length,
+    active: active.length,
+    avg,
+    climbing: players.filter(p => p.ratingChange != null && p.ratingChange > 0).length,
+    slipping: players.filter(p => p.ratingChange != null && p.ratingChange < 0).length
+  };
+}
+
 module.exports = {
   getPlayerDataFromDB,
   scrapePDGARating,
   getPredictedRatingFromDB,
   getAllRatingsFromDB,
-  refreshAllPlayersInDB
+  refreshAllPlayersInDB,
+  computeKpis
 };